Designating a Network Interface as Primary

Many DHCP configuration parameters are not specific to a network interface. Instead, the parameters specify more general information. Examples of this type of general parameter are: NIS server, NIS domain, DNS servers, and DNS domain. If your Solaris machine has only a single network interface, there does not need to be a distinction between the general and interface-specific parameters.

However, if your machine has multiple network interfaces (it is multihomed), and DHCP is to configure more than one interface, then it is possible to receive multiple sets of general configuration parameters that may conflict. For example, which DNS parameters should be used? Those received when using DHCP to configure interface le0 or those received for le1?

The Solaris DHCP client solves this problem by allowing you to specify one network interface as the primary network interface. Interface-specific parameters (such as subnet mask) will be retrieved from the DHCP parameters for that specific interface. General parameters are retrieved only from the DHCP information received on the primary interface.

To designate a network interface as the primary interface, add the keyword primary to the DHCP enable file for that interface. For example, suppose you want to use qe2 as the primary interface. Edit /etc/dhcp.qe2 and add the word primary.

If the keyword primary is not added (no interface has been designated as primary), the Solaris machine receives parameters from the first interface that is configured successfully.